400/4 cyl.head

[kenny1059]

Hi,
Could someone please tell me if the holes marked in blue in pic,can be helicoiled o.k.  They seem very close to camshaft bearing.
cheers, Kenny.

[PatM]

Ken by, I've never used helicoils as I don't trust them. If that was mine, I'd tap the holes with a blind tap, next size up. They are very close to the wall, as you say. You start a blind tap with a taper tap, the once the first few threads are cut, swap over. A blind tap has a flat top, rather than a point, if you follow.

[Bryanj]

They can be helicoiled with care, the next normal size up is 8mm which may be too big, i believe helicoils are 7 to 7.5 mm OD

[Clem2112]

Yes.
Had a few of mine done including that dodgy looking thin walled one !
It looks like Honda made a small mistake with the casting designs.

I use a local engine machining specialist who charge a couple of quid per repaired hole.
In time all these will try to strip if the cover comes off enough times.

[Trigger]

Your not wrong on that Oddjob. That head is showing a lot of overheating marks and oil starvation, what is the cam shaft like???

[kenny1059]

Agreed it is not the best of heads. Anybody know where I can find a better one? I have another head,but it is in a far worse state.
The camshaft has very slight marking on it. Should be o.k.   b.t.w. The marks on the l/h bearing are drips of oil.
Might tap them M7,if I don't go the helicoil way.
  cheers,  Kenny.

[Trigger]

OK, found my glasses. Sill showing a oil starvation problem. Could work with a 7mm tap. I would still be looking for another head with those marks. If you could line bore these heads it would be a lot easier.

[AshimotoK0]

OK, found my glasses. Sill showing a oil starvation problem. Could work with a 7mm tap. I would still be looking for another head with those marks. If you could line bore these heads it would be a lot easier.

Just read the latest Classic Bike article on the 400/4 they are restoring and the head they have has been fitted with Kawasaki shell bearings (by PO) in the head and the cam cover had been replaced with a new one. I always assumed that the cam cover would be line bored with the head but obviously not the case. Never seen anyone fit shell bearing before only needle rollers to a 500/4 from memory. (and on the twins but that's a totally different arrangement with two end caps).

Cheers ... Ash

[Trigger]

Ash, if you have a head with end caps it can be white metal and line bored. No end caps is a problem.

[AshimotoK0]

I've now got two nice sets of end caps for the 250 (took some bleedin finding though.. usual German transaction rather than eBay UK 'well they look serviceable mate rubbish'). I have also got a worn pair and all of the needle roller parts and spacers etc (Timken) to do a needle conversion with them. Think I am just going with standard and bung all of the needle roller bits on eBay sometime. Don't let anyone on HondaTwins.net tell you those needle roller components can be had for $50 ... even with mega trade discount they cost double that ( well for decent quality and with the oil hole in anyway).

I did once see a CB360G5 with cam bearings that were phosphor broze bush inserts. Problem is you need to 'scallop' out a bit to let the oil puddle... OK if you are an experienced machinist but there is not much 'meat' to bore into.

Cheers ... Ash

[kenny1059]

Thanks for replies guys. I am looking for another/better head.
Is the cyl. head of a 400/4 the same as a 350/4 ?
  cheers, Kenny.

[Bitsa (Ralph Wright - RIP)]

Kenny
Dont take my word for this but  I remember reading that when the 350 came out it did not go to the UK GUTLEES AS i RECALL .For the Uk Honda redid the stroke etc to take it to 406? so in my opinion they did not do a new head maybe be wrong but I am sure the others will corect me.
Chhers
Bitsa

[Bitsa (Ralph Wright - RIP)]

f ME  WHAT THE CRAP HAS HAPPENED TO THE SPELLING?

[Trigger]

You should of gone to school Bitsa instead of chasing girls.

[kenny1059]

 
   cheers, Kenny.